Generic power-branched transmissions are used in work machines or agricultural machines, such as tractors, in which the external shape of the transmission has to be long and slender.
A power-branched transmission that has a variator configured as a hydrostatic device is known from DE 10 2006 025 348 A1. The power-branched transmission is equipped with a power splitting planetary gear set, wherein a shaft of the planetary gear set is operatively connected to a first shaft of the variator and drives a variable displacement pump by means of it. Another shaft of the planetary gear set is connected via a gear stage to another shaft of the variator, which in turn is operatively connected to the hydraulic motor of the variator. The third shaft of the planetary gear set is connected to a transmission input of the power-branched transmission, which is connected to a drive mechanism. In addition, the second shaft of the variator is configured with a plurality of fixed gears, which mesh with a plurality of idler gears that are arranged on a countershaft, wherein the idler gears can be connected, via shift elements, to the countershaft in a rotationally fixed manner for implementing different drive modes and/or transmission ranges for forward driving and at least one drive mode for reverse driving.
Disadvantageously, the changes between drive modes cannot be carried out synchronously, so that power shifting with simultaneous correction of the transmission ratio in the region of the hydrostatic device has to be carried out in order to avoid interruption of the torque flow at any rate when changing a drive mode. During such shifts, disturbing reaction torques occur in the drive train that can be perceived as a jerk by the operator during operation.